As the twentieth century came to a close, the raw materials for a great national literature were at hand, waiting _______.(2006年湖南省高考) A. to use B. to be used C. to have used D. to be using 答案:B
如图所示,一长方体木块,置于同一粗糙水平面上,甲中木块竖放,乙中木块平放,丙中木块平放并在其上加一重物,在甲、乙、丙三种情况下,匀速拉动长方体所需的水平力分别为F甲、F乙、F丙,则下列关系正确的是
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A.
F甲<F乙<F丙
B.
F甲>F乙>F丙
C.
F甲<F乙=F丙
D.
F甲=F乙<F丙